1. Department of Medicine and Surgery, University of Milano Bicocca , Monza, Italy,
2. Department of Public Health, Experimental and Forensic Medicine, University of Pavia , Pavia, Italy,
3. EMCDDA , Lisbon, Portugal,
4. Istituto de Higiene e Medician Tropical Universidade Nova de Lisboa , Lisbon, Portugal, and
5. Division of Psychiatry, Faculty of Brain Sciences, University College of London , London, UK